title: Neuronal voltage-gated potassium channel complex autoimmunity in children.
abstract: Autoimmunity targeting voltage-gated potassium channel complexes have not been systematically documented in children. Identified in the Neuroimmunology Laboratory records of Mayo Clinic were 12 seropositive children, 7 among 252 Mayo Clinic pediatric patients tested on a service basis for serologic evidence of neurologic autoimmunity (June 2008-April 2010), 4 during the assay's preimplementation validation (before June 2008) and 1 non-Mayo patient with available clinical information. Neurologic manifestations were subacute and multifocal. Three had global developmental regression, 6 movement disorders, 4 dysarthria, 3 seizures, 1 Satoyoshi syndrome, 1 painful red feet, 2 insomnia, 2 gastrointestinal dysmotility, and 2 small fiber neuropathy. Neoplasia was found in 1 child. Treating physicians recorded improvement in all 7 children who received immunotherapy. Neurologic symptom relapse occurred in 3 of 6 children after ceasing immunotherapy. These findings highlight a diverse clinical spectrum of neuronal potassium channel complex autoimmunity in children, and they illustrate benefit from early initiated immunotherapy, with a tendency to relapse when therapy ceases. Diagnosis is generally delayed in the process of eliminating neurodegenerative causes. Currently 2.7% of pediatric sera evaluated for neurologic autoimmunity are positive for neuronal potassium channel complex-reactive immunoglobulin G. The frequency and full spectrum of neurologic accompaniments remains to be determined.
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Radhika
authors.initials: R
authors.lastname: Dhamija
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Renaud
authors.forename: Sean J
authors.initials: SJ
authors.lastname: Pittock
authors.forename: Andrew
authors.initials: A
authors.lastname: McKeon
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Lachance
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Nickels
authors.forename: Elaine C
authors.initials: EC
authors.lastname: Wirrell
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Kuntz
authors.forename: Mary D
authors.initials: MD
authors.lastname: King
authors.forename: Vanda A
authors.initials: VA
authors.lastname: Lennon
mesh_terms: D000293:Adolescent; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000097:blood* / Q000276:immunology / Q000628:therapy*; D015551:Autoimmunity / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D047468:Immunoprecipitation / Q000379:methods; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D008297:Male; D009369:Neoplasms / Q000209:etiology; D010951:Plasma Exchange / Q000379:methods; D024642:Potassium Channels, Voltage-Gated / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D007166:Immunosuppressive Agents; D024642:Potassium Channels, Voltage-Gated